1. Field of the Invention
This invention relates to an electronic control device and its circuitry for providing control values, particularly, control values having direction and magnitude, and more specifically, it relates to improvements in electronic control devices employing capacitive electrodes, shaped so that the capacitance is proportional to the area or distance effectively changed when a conducting member is positioned adjacent to the electrodes and moved from one position to another with respect to the electrodes.
2. Description of the Prior Art
There are many types of electronic control devices for generating and translating positional information into electrical signals. An example of an application for these electrical signals is a cursor control device which may be used in visual display apparatus such as those used in text editing or in video games based upon a circuitry with one or two dimensional implementation. A cursor can be controlled in both ways, line by line, or in graphics in two dimensions. One or two dimensional implementation in control devices is also presently known which functions electronically as a mechanical "joystick" which generally is a pivoted mechanical lever or control member with freedom of movement in a 360 radius, and which device is used in conjunction with controlling quadrophonic sound systems, video games, or vehicles, such as aircraft and boats.
The prior art has generally described positional indicator devices with two dimensional implementation and operated through the employment of a mechanical joystick. Illustrative are U.S. Pat. Nos. 4,190,834; 4,305,007; 4,364,047; and 4,459,578. The electronic circuitry of the prior art may employ capacitative effect components, or registers and counters in a logic circuit, or the Hall Effect with the intended purpose for direction control. In most of these examples, the displacement of the joystick generates two electrical signals representative of cartesian x, y values.
Since these mechanical joystick devices hereinbefore described employ moving parts, they are susceptible to wear, inaccuracies due to misalignment of components, or mechanical limitations, and/or slow response time. Another problem is the tendency to inadvertently activate the control system due to the generally upright positioning of the joystick member.
To reduce, if not eliminate, the impact of these disadvantages, ideally there must exist an electronic position indicating device which is essentially electrical not requiring any moving parts. Such a device may be controlled by a finger touch panel, for example.
The prior art has also shown a finger touch panel for position control with two dimensional implementation. Illustrative is U.S. Pat. No. 4,177,421 where a finger touch control panel comprises two or more capacitive transducers to as an x-y position indicating control. Also illustrative is U.S. Pat. No. 4,103,252 which device functions on the principle of variable capacitance caused by finger movement on the surface of the device in proximity to a plurality of capacitor plates. These devices have no moving mechanical parts, but require sophisticated electronic circuitry for sensing the variance of capacitance to provide signal outputs representative of x, y position coordinates.
There is therefore lacking in the prior art a teaching of a generally total electronic device with finger sensitive control adaptive for versatile use in video, sound, and vehicle control systems. There is further lacking such a device containing a simple inexpensive electronic circuitry employing capacitive effect for producing electrical outputs representative of direction and magnitude for position of a control member. There is further lacking in the prior art a one dimensional finger sensitive control panel which cannot inadvertently be contacted, and activating the electronic circuitry or control system. There is further lacking in the prior art finger sensitive control means employed in an inexpensive, yet extremely rugged enclosure carrying the electronic circuitry and manufactured in a variety of shapes and sizes for specialized uses. There is further lacking a positional control device which is not easily affected by acceleration or vibration occurring in the system.